So slow is the flow of our spring-fed river that a solid mat of duckweed has clogged the bend, leaving the impression that the current has ceased altogether. In the water under a footbridge, waving fronds and cabbage-like scrunched leaves wave no more, but there is anything but stillness here - shoal upon shoal of fish, partitioned both by species and size, plait and dart with purposeful randomness over the bricks and stones of an algae-coated riverbed.
Beneath my feet, the minor minnows cluster. Farther out, in a glade enclosed by waterweed, curiosity nudges a shoal of sprat-sized fish towards the awning of vegetation. They might seek to hide and forage here, though it's always possible something else might have got there first.
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And so it proves. The whole shoal whips back in an instant recoil, whisked away as one from what they have half-seen in the shadows. Now begins that so often witnessed, apparently reckless and insane charade in which repulsion and attraction do battle in the minds of prey. Fear holds them back, but doubt and inquisitiveness start to inch the shoal forward again. What exactly lurks there and is it actually dangerous? Could they just get a better look?
All this while, I am half-watching a pond skater skimming towards this perilous scene. Legs feel for surface vibration, eyes focused on the above, not thinking - if it thinks at all - about what might come up from below. A tiny part of the river erupts, a belch, a snap, the water bulges into a dome for a moment, then subsides to level calm.
Its cover blown, the giant perch cruises into the glade, flashing its dull tiger stripes, and the shoal parts before it. This old fish, maybe half a metre long, has the saggy look of a plastic shark with a slow puncture. Misshapen by the big triangular hump between its head and dorsal fin that comes with age, the perch shimmies unhurried out into the open pool of the weir. At this, a great shoal of medium-sized, smooth-bodied fish rises out of the depths and forms a train at its tail. Keeping their distance, of course.
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